Trestle clamp



Jul/y s', 1947. H. D STRAND 2,423,735

TRESTLE CLAMP HARO/ D D. STE/IND TTok/vsYs' July 8, 1947.

H. D. S'TRAND TRESTLE -CLAMP Filed Dec. 6, 1945 2 Sheets-Sheet 2 ANVENTOE HARO/ D. STE/IND j @Ml fm ATTORNEYS Patented July 8, 1947 iUNITED STATES PATENT OFFICE TRESTLE CLAMP Harold D. Strand, St. Paul,Minn.

Application December 6, 1945, Serial No. 633,223

(Cl. S04-'5) 7 Claims.

This invention relates to a trestlek clamp and more particularly to aclamp for demountably clamping together the supporting legs of a trestleand the cross plank or beam or support; connecting two such clampingmeans. This novel device is adapted toY form a trestle such as is'usedby carpenters, masons, plasterers, etc. and is of the knock-down typewherein substantially a minimum number of relatively small parts of acomplete trestle need be transferred from one job to another. It doesnot employ bolts, nuts, screws or nails and lends itself to inexpensiveproduction and to simplicity in use.

It has been common practice to construct trestles wholly of wood eitheron the site of each particular job or to construct them and convey themfrom one job to another. The construction of trestles at the place ofeach particular job is time-consuming'and expensive and the conveyanceof pre-constructed trestles from one jobto another is inconvenient andexpensive.

An object of the invention is to provide a simple and efcient form oftrestle clamp of the knock-down type.

Another object is to provide such a trestle clamp with a few sturdyparts which. may be easily and conveniently transported from one job toanother.

Embodying the above objects and others which may hereinafter appear, theinvention consists in the novel construction, combination andarrangement of parts as will be more specicallydescribed and illustratedin the accompanying drawing wherein is shownan embodiment of theinvention, but it is to be understood that changes,

Variations and modifications may be resorted to y within the scope ofthe invention as claimed.

In the drawings:

Figure l is a view in side elevation of a pair of novel clamps inassembled relation with supporting legs and a cross beam, the clamp onythe right having an outside portion cut away to show the interior;

Figure 2 is a vertical section on the line 2-2 of Figure 1 and showingthe parts in assembled clamping relation;

Figure 3 is a view similar to Figure 2 but showing the position of theparts before being moved to clamping position;

Figure 4 is a plan view of the left end of the trestle shown in Figure1;

Figure 5 is a cross-section on the line 5 5 of Figure 2 and particularlyshowing the tops of the abutment members carried by the clampingelements; ,Y

Figure 6 is a cross-section on the line 6 6 of Figure 2 and particularlyshowing the lower guide members and the lower clamping portions of theelements; and

Figure 7 is a view on the line 1--1 of Figure 1 showing the connectionof the diagonal braces to the ledger or cross beam.

Referring to the drawings and particularly to Figure l thereof, there isshown an assembled trestle of the type used by carpenters, masons,plasterers, etc., to provide a platform elevated above the ground orfloor level and by the use of which workmen may have ready access toareas normally beyond reach and for other well-known purposes. In theordinary use of such trestles two of them are positioned in spacedrelation to act as a supporting means for one or more iiat boardsspanning them and thus providing a temporary ooring. Of course, such asingle trestle may be used as a supporting structure from which objectsmay be suspended such as a swing.

This trestle clamp is well adapted for use with the ordinary 2 x 4lumber of which trestles are ordinarily constructed and of which lumberthere is usually anfadequate supply.

This novel clamp is preferably made in a substantially trapezoidal formwith two side members. and upper and lower connecting side members. Eachof the outer members 8 and 9 is preferably formed of relatively rigidchanneled material, such as iron, with the channels inwardly opposed. Asshown in the drawings these Vtwo outer members are preferably disposedin upwardly converging relation. Each of theupper outer opposite sidesof these outer members is connected by a cross bar lll while the similarlower opposite sides are connected by a cross bar H. These four crossbars are xedly secured to thev outer members as for example by weldingor brazing.

Each one of the clamping elements l2 and I3 is formed of relativelyrigid channeled material such as iron and the channels inwardly facealthough each clamping member (like the outer members) could well beformed of non-channeled rigid material. These clamping elements areunited, as by welding, at the lower ends by'a base I. This base isdesirably formed oi a relatively resilient metal and the lower end ofeach clamping element vis welded to its upper face. The base extendsoutwardly beyond the clamping elements as shown in Figures 2 and 3 andeach opposite end of the base ill is provided with a downwardly curvedclamping face i5. The advantage of the use of a relatively resilientmaterial for the base I4 resides in the fact that it permits the upperunconnected ends of the clamping elements to be spread apart to receivea ledger or trestle beam I 6.

These two clamping elements have a guided movement relative to thetrapezoidal structure. Extending across the top of the structure betweenthe upper cross bars are two guide bars I'I as shown in Figure 4.Similar guide bars I8 are adjacent the lower end of the structure andextend between the lower crossV bars I I. These upper and lower crosshars at their intermediate portions are provided with recesses I9 withinwhich the clamping members are positioned for guided relative movement.

Somewhat above the middle portion of each clamping element and on theouter face of each thereof is welded or otherwise secured an angledbracket constituting an abutment 2i). Each abutment as shown in Figures2 and 3 is substantially L-shaped and is welded to the base at itsangled portion so that the two sides of the L extend at an angle to theplane of the back ofeach clamping member. v Y

Preferably a boss 2l is placed on the outer face of one of the clampingelements. This boss may be formed by a few drops of melted iron and itsfunction is normally to prevent the downward descent of the relativelyslidable clamping elements through the guide bar recesses I9. While theboss normally prevents accidental disassociation of the clamping barsand the structure, yet the clamping bars may be forced together at theirupper ends suiciently so that the boss 2| willpass through the lowerguide bar recess. In normal use it is preferred to have the clampingelements remain with the structure.

This clamping 1 structure also preferably includes a pair of brace rods22. Each brace rod consists of a U-shaped rod pivotally mounted in asleeve 23 Welded to the exterior of one of the lower cross bars. EachYof the two free ends of the brace rods has fastened thereto an openended staple 24 with the sharpened points opposing each other. The bracerod 22 is adapted to be upwardly swung when the trestle beam is inposition with one stapleon one side of the beam and the other on theopposite side. Preferably a metallic plate 25 with two guide holes ismounted upon the U-shaped brace. When the plate 25 is in its loweredposition, as shown in Figure 6, the outer ends of the brace may beeasily parted to straddle the trestle beam as there shown. In assemblythe plate 25 is manually outwardly mowed to the position shown inFigures 1 and 4 so that the'pointed ends of the staples 24 are firmlyembedded in the'side of the wooden beam IE and there held.

lIhe simplicity of assembly is well shown in Figures 2 and 3. As shownin Figure 3, the .clamping elements I2 and I3 are in their lowerpositions. A ledger or common form of trestle beam I6 has been looselyplaced between the upper ends of the two clamping elements while twosupporting legs 26 of a common 2 x 4 lumber have been inserted withinthe'outer members 8 and 9. These 2 x 4 legs may be of any convenientlength to give the desired height to the assembled trestle. The upperends of the wooden legs abut against the outwardly projecting'faces ofthe angled abutments 20 while-the clamping faces I5 are out ofengagement with the inner faces of thelegs. .Y

One simplemode of clamping is to turn the associated parts (Figure Y3)upside down and then Y grasp the legs and downwardly press them with thebeam I6 Yupon the gro-unduntil the assembly binds and then forciblypoundl or bang the assembly against the beam I6 upon the ground. Suchforce causes the beam I6 to force the upper cross bars I0 and theconnected outer members 8 and 9 upwardly (being inverted) so that theparts are forced to the position shown in Figure 2 when that figure isinverted. The wooden legs, as a result of the impact downwardly, forcethe two abutments 20 downwardly and thus cause the two clamping elementslikewise to move relatively to the outer members so that the partsassume the clamped position disclosed when one inverts Figure 2 of thedrawings.

Thereafter the assembled clamped parts are restored to the uprightposition as viewed in Figure 2 when restored to normal position whereinit is seen that the clamping faces I5 of the base I4 have forciblyclamped the supporting legs and the upper or outer ends of the channeledclamping elements I2-I 3 have been relatively upwardly and inwardlymoved to clamp the trestle beam.

Y'Ifhe clamps are adapted for use in pairs with a ledger or beam I6extending between them. Obviously any weight borne by the beam I6 onlyclamps the parts more rmly togethen Additional fixation of the assembledtrestle is .provided by the brace rods 22 which are next placed inposition as heretofore described. While the above mode of assembly seemsto be the most convenient, one may also assemble the parts in theposition shown in Figure 3 and then hammer or pound the beam IBdownwardly so that the outer members 8 9 are downwardly forced along thesides of the legs 26 which rest upon the ground or oor. Such relativemovement causes the clamping faces I5 to engage and clamp the innerfaces of the supporting legsand the result is the same as abovedescribed.

' After use the clamped parts may easilyV be disassociated by upwardlypounding either cross bar IIlor II of the shortermembers whereby thebeam is released and removed from the clamping elements and thereafterupwardly pounding the lower cross bar I I of the outer members wherebythe outer members are upwardly moved relatively to theY clampingelements from the position in Figure 2 to that of Figure 3 whereupon thetwo supporting legs are unclamped and may easily be removed.

It will berapparent to those skilled in the art that I have acomplishedat least the principal objects ofV my invention,Y and it .will also beapparent to those skilled in the art that the embodiments hereindescribed may be variously changed and modified without departing fromthe spirit of the invention, and that the invention is capable of usesand'has advantages not herein specifically described ;-'hence it'will beappreciated that the herein disclosed embodiments are illustrative only,and that my invention is not limited thereto.

I claim as my invention:

1. A trestle clamp adapted to secure together a pair of supporting legsand a transverse beam in clampedassembled relation; comprising a pair ofspaced outer members, means rigidly connecting the outer members to eachother to provide a hollow structure, a pair of relatively movableclamping-elements positioned within the structure to permit insertion ofone of said supporting legs'at eachside between an outer member and aclamping element, the elements'being spaced apart at theirv upper 'endsto'receive said transverse beam, clamping means carried adjacent thelower end of each element to engageY anyadjacent side'of'an inserted legwhereby, upon forced relative movement of the clamping elements andstructure, the legs and beam are securely held in clamped relation.

2. A trestle clamp having two side members and upper and lowerconnecting members forma side member and a clamping element, theelements being spaced apart at their upper ends to receive atrestle-forming instrumentality, clamping surfaces carried adjacent thelower end of each element to engage a side of an inserted leg whereby,upon relative movement of the elements and side members, the legs andinstrumentality are securely held in clamped relation.

3. A trestle clamp comprising two outer members spaced apart, meansrigidly securing together the upper and lower portions of the members,guides carried by said securing means, clamping elements slidably borneby the guides, a base resiliently connecting the lower portions of saidclamping elements whereby the upper portions` of the elements may beforced apart to receive and tensionably grip a trestle device, clampingmeans on each end of said base and adapted to engage and clamp asupporting leg inserted between each clamping means and an outer memberwhereby said .parts may be assembled into clamping relation uponrelative movement of the outer members and the clamping elements.

4. A trestle clamp comprising two outer members spaced apart, upper andlower cross-bars pair of supporting legs and a transverse beam inclamped assembled relation, comprising a pair of spaced outer members,means rigidly connecting together the outer members to provide a hollowstructure, a pair of relatively movable clamping elements positionedwithin the structure to permit insertion of one of said supporting legsat each side between an outer member and a clamping element, theelements being spaced apart at their upper ends to receive saidtransverse beam, an abutment xedly carried by each element and extendinginto the space between such element and the inner face of the opposedouter member so that the upper end of each inserted leg may terminallyengage an abutment, clamping means adjacent the lower end of eachelement to engage an adjacent side of an inserted leg whereby, uponforced relative movement of clamping elements and structure, the legsand beam are securely held in clamped relation.

7. A trestle clamp comprising, two outer members disposed in upwardlyconverging opposed relation, each outer member being formed ofrelatively rigid channeled material with the channels inwardly opposing,upper cross bars at the upper outer sides of the outer members rigidlysecuring them together, lower cross bars at the lower outer sides of theouter members rigidly securing them together, guide bars extendingbetween the upper 0 cross bars in spaced relation, guide barsextendrigidly securing the upper and lower portions of the memberstogether, guides carried by the upper and lower cross-bars, clampingelements slidably borne by the guides, a base resiliently connecting thelower endportions of said elements,

the upper portions of said elements being spaced to receive a trestlebeam, clamping means on each` end of said base adapted to engage anadjacent face of an inserted supporting leg whereby upon forced relativemovement of the clamping elements and the outer members the supportinglegs and beam are securely clamped together.

5. A trestle clamp comprising two outer members disposed in opposedupwardly converging relation, each outer member being formed of rigidchanneled material with the channels inwardly opposing, upper and lowercross bars at the upper and lower outer sides of the outer membersrigidly securing them together to form a substantially trapezoidalstructure, guide bars extending in spaced relation between the lowercross bars, a pair of spaced clamping elements extending upwardlybetween the inner faces of the guide bars and movable therebetween, theupper portions of the clamping elements being spaced to receive atransverse beam, a relatively whereby upon forced relative movement ofthe 6 clamping elements and said structure, the supporting legs and beamare securely clamped together.

6. A trestle clamp adapted to secure together a ing between the lowercross bars in spaced relation, the cross bars and the outer membersform.. ing a relatively rigid substantially trapezoidal structure, apair of spaced clamping elements extending upwardly between the innersurfaces of the upper and lower guide bars and slidable therebetween, arelatively resilient base fixedly secured to the lower ends of theclamping elements, the base having a downwardly extending clamping faceat each end, an abutment on the outer side of each clamping element,said structure being adapted to receive a supporting leg at each sidebetween the inner face of each outer member and the clamping face on theclamping base with each upper end of each supporting leg positionedagainst one of said abutments, the space clamping elements normallyextending above the Itop of the structure and adapted to receivetherebetween a trestle support, whereby when the supporting legs andtrestle support are initially assembled the outer members and clampingelements may be forcibly moved relatively to each other to cause thebase clamping faces to clamp the legs against the inner faces of theouter members and the upper portions of the clamping elements clamp thetrestle support.

HAROLD D. STRAND.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED sTATEs PATENTS Number yName Date 2,162,651 Thomson June 13, 19391,816,198 Sample July 28, 1931 2,096,668 Brown Oct. 19, 1937 1,996,761Gould et al. Apr` 9, 1935

